Hand operated tools for cutting tubing, light pipe, and other cylindrical materials are well known. Such devices Generally include at least one cutting blade or wheel positioned opposite at least two guide rollers, to capture the material being cut between the cutting blade and rollers at three contact points. The tool is rotated about the material being cut (or the material is rotated within the tool) to cause the cutting blade to pass circumferentially about the material.
As the material is being cut, the bottom of the groove formed in the cut material of course defines a smaller diameter than the uncut material. Accordingly, some means must be provided to advance the cutting blade toward the guide rollers, in order to continue to deepen the cut. Heretofore, the general method used for such cutting blade advancement was to manually and threadedly advance the cutting blade after each turn or two about the material; the cutting blade is positively secured by a threaded screw mechanism in such tools.
Such manual advancement of the cutting blade is tedious, and can lead to damage and/or misalignment of the rotating cutting blade if too much force is used to advance the blade. Obviously, such a tool requires a fair amount of patience on the part of the user.
Accordingly, a spring biased tubing cutter tool has been developed, in which the cutting blade is urged toward the guide rollers by spring means. Various embodiments of this tool are disclosed in the present inventor's previously issued U.S. Pat. No. 5,206,996, discussed in detail in the Description Of The Prior Art further below. However, other features (e. g., proper alignment of the cutting blade wheel relative to the guide rollers) must also be considered in order to provide for cutting different diameters of material. The present inventor's previously issued patent provided for such by various means in at least some embodiments, but those mechanisms all incorporated the positive capture of the cutting blade in the jaw opposite the guide roller jaws, with the accompanying complications of attempting to provide linear movement of the cutting blade relative to the rollers, in an arcuately moving jaw assembly.
The present invention responds to this problem by providing a simplified means of maintaining linear alignment between the cutting blade and the guide rollers, by securing the cutting blade within the tool in such a way that it is not positively captured by the jaw opposite the guide roller jaw. The cutting blade holder slides relative to the cutting blade jaw, thereby allowing the jaws to move arcuately relative to one another, while still allowing the cutting blade to move linearly toward or away from the guide rollers to maintain proper alignment on any material diameter.